Predictors of response to intravesical dimethyl-sulfoxide cocktail in patients with interstitial cystitis

To identify predictors of treatment failure of dimethyl sulfoxide (DMSO) "cocktail" for patients with interstitial cystitis (IC).

Fifty-one IC patients received weekly intravesical instillations of "cocktail" composed of 50% DMSO (50 mL), 100 mg of hydrocortisone (5 mL), 10,000 U of heparin sulfate (10 mL), and 0.5% bupivacaine (10 mL) for 12 weeks. A reduction from baseline in the O'Leary-Sant questionnaire score of ≥ 30% was considered as a response. Patients were evaluated every 3 weeks during the treatment course and at 1, 3, 6, 9, and 12 months thereafter. In addition, patients filled in a 3-day bladder diary and a 0-10 visual analogue scale (VAS) for pain. Responders and nonresponders were compared and predictors of treatment failure were identified using univariate analysis and multiple logistic regression.

Thirty-one patients (61%) were responders. A significant decrease from baseline in the mean questionnaire's score (27.2 ± 2.8 vs 18.8 ± 2.0, P = .0001) was noted in the responders group. Improvements in the mean daily number of micturitions (16.7 ± 3.6 vs 14.8 ± 2.8, P = .003) and in the mean VAS (7.6 ± 1.6 vs 3.6 ± 1.0, P = .0001) were noted as well. In the nonresponders group, none of these variables improved significantly. Patient age, menopausal state, body mass index, diabetes mellitus, and cystometric and anesthetic capacities were all associated with response. However, only an anesthetic bladder capacity <675 mL independently predicted treatment failure (odds ratio 83, 95% CI 9-714, P < .0001).

Intravesical cocktail for IC patients is associated with a 61% response rate. A small anesthetic bladder capacity predicts treatment failure.